/* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */

#include "sql_priv.h"
#include "my_global.h"                          // HAVE_REPLICATION

#ifdef HAVE_REPLICATION

#include "rpl_tblmap.h"
#ifndef MYSQL_CLIENT
    #include "table.h"
#endif

#ifdef MYSQL_CLIENT
    #define MAYBE_TABLE_NAME(T) ("")
#else
    #define MAYBE_TABLE_NAME(T) ((T) ? (T)->s->table_name.str : "<>")
#endif
#define TABLE_ID_HASH_SIZE 32
#define TABLE_ID_CHUNK 256

table_mapping::table_mapping()
    : m_free(0)
{
    /*
      No "free_element" function for entries passed here, as the entries are
      allocated in a MEM_ROOT (freed as a whole in the destructor), they cannot
      be freed one by one.
      Note that below we don't test if my_hash_init() succeeded. This
      constructor is called at startup only.
    */
    (void) my_hash_init(&m_table_ids, &my_charset_bin, TABLE_ID_HASH_SIZE,
                        offsetof(entry, table_id), sizeof(ulong),
                        0, 0, 0);
    /* We don't preallocate any block, this is consistent with m_free=0 above */
    init_alloc_root(&m_mem_root, TABLE_ID_HASH_SIZE * sizeof(entry), 0);
}

table_mapping::~table_mapping()
{
#ifdef MYSQL_CLIENT
    clear_tables();
#endif
    my_hash_free(&m_table_ids);
    free_root(&m_mem_root, MYF(0));
}

TABLE *table_mapping::get_table(ulong table_id)
{
    DBUG_ENTER("table_mapping::get_table(ulong)");
    DBUG_PRINT("enter", ("table_id: %lu", table_id));
    entry *e = find_entry(table_id);

    if (e) {
        DBUG_PRINT("info", ("tid %lu -> table 0x%lx (%s)",
                            table_id, (long) e->table,
                            MAYBE_TABLE_NAME(e->table)));
        DBUG_RETURN(e->table);
    }

    DBUG_PRINT("info", ("tid %lu is not mapped!", table_id));
    DBUG_RETURN(NULL);
}

/*
  Called when we are out of table id entries. Creates TABLE_ID_CHUNK
  new entries, chain them and attach them at the head of the list of free
  (free for use) entries.
*/
int table_mapping::expand()
{
    /*
      If we wanted to use "tmp= new (&m_mem_root) entry[TABLE_ID_CHUNK]",
      we would have to make "entry" derive from Sql_alloc but then it would not
      be a POD anymore and we want it to be (see rpl_tblmap.h). So we allocate
      in C.
    */
    entry *tmp = (entry *)alloc_root(&m_mem_root, TABLE_ID_CHUNK * sizeof(entry));

    if (tmp == NULL)
        return ERR_MEMORY_ALLOCATION; // Memory allocation failed

    /* Find the end of this fresh new array of free entries */
    entry *e_end = tmp + TABLE_ID_CHUNK - 1;

    for (entry *e = tmp; e < e_end; e++)
        e->next = e + 1;

    e_end->next = m_free;
    m_free = tmp;
    return 0;
}

int table_mapping::set_table(ulong table_id, TABLE *table)
{
    DBUG_ENTER("table_mapping::set_table(ulong,TABLE*)");
    DBUG_PRINT("enter", ("table_id: %lu  table: 0x%lx (%s)",
                         table_id,
                         (long) table, MAYBE_TABLE_NAME(table)));
    entry *e = find_entry(table_id);

    if (e == 0) {
        if (m_free == 0 && expand())
            DBUG_RETURN(ERR_MEMORY_ALLOCATION); // Memory allocation failed

        e = m_free;
        m_free = m_free->next;

    } else {
#ifdef MYSQL_CLIENT
        free_table_map_log_event(e->table);
#endif
        my_hash_delete(&m_table_ids, (uchar *)e);
    }

    e->table_id = table_id;
    e->table = table;

    if (my_hash_insert(&m_table_ids, (uchar *)e)) {
        /* we add this entry to the chain of free (free for use) entries */
        e->next = m_free;
        m_free = e;
        DBUG_RETURN(ERR_MEMORY_ALLOCATION);
    }

    DBUG_PRINT("info", ("tid %lu -> table 0x%lx (%s)",
                        table_id, (long) e->table,
                        MAYBE_TABLE_NAME(e->table)));
    DBUG_RETURN(0);		// All OK
}

int table_mapping::remove_table(ulong table_id)
{
    entry *e = find_entry(table_id);

    if (e) {
        my_hash_delete(&m_table_ids, (uchar *)e);
        /* we add this entry to the chain of free (free for use) entries */
        e->next = m_free;
        m_free = e;
        return 0;			// All OK
    }

    return 1;			// No table to remove
}

/*
  Puts all entries into the list of free-for-use entries (does not free any
  memory), and empties the hash.
*/
void table_mapping::clear_tables()
{
    DBUG_ENTER("table_mapping::clear_tables()");

    for (uint i = 0; i < m_table_ids.records; i++) {
        entry *e = (entry *)my_hash_element(&m_table_ids, i);
#ifdef MYSQL_CLIENT
        free_table_map_log_event(e->table);
#endif
        e->next = m_free;
        m_free = e;
    }

    my_hash_reset(&m_table_ids);
    DBUG_VOID_RETURN;
}

#endif
